SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '122db3f8a70000501086c190811934c7ab3cfb22051f30742788a1df98138be5' 
  AND token = 'N1uVF92byyTbS+qka0ChIqavAREaJIOo9Uqo01HroWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}